As semiconductor light-emitting elements including a semiconductor multilayer film, light emitting diodes (in the following, referred to as “LEDs”) have been known. Among them, LEDs emitting blue light such as GaN LEDs can be combined with a phosphor that is excited by blue light and emits fluorescence, and thereby applied to semiconductor light-emitting devices emitting white light.
FIG. 12 is a sectional view showing a conventional semiconductor light-emitting device emitting white light. As shown in FIG. 12, in a semiconductor light-emitting device 100, an LED chip 102 emitting blue light is fixed firmly on a bottom surface of a recessed portion provided at one end of a first lead frame 101a, using a chip fixing paste material 103 formed of an Ag paste or the like.
An upper surface of the LED chip 102 is provided with a first electrode 104a and a second electrode 104b. The first electrode 104a is connected electrically with the first lead frame 101a via a first wire 105a, whereas the second electrode 104b is connected electrically with a second lead frame 101b, which pairs up with the first lead frame 101a, via a second wire 105b. 
The LED chip 102 is sealed by a phosphor layer 106 that is shaped like an artillery shell. A binder for the phosphor layer 106 generally can be a resin material that transmits visible light such as an epoxy resin or a silicone resin. Further, in the phosphor layer 106, a phosphor 106a is dispersed (for example, see Patent document 1).
However, when using the epoxy resin or the silicone resin as the binder for the phosphor layer in the conventional semiconductor light-emitting device described above, there arise the following problems.
In the case of using the epoxy resin, since the epoxy resin has a considerably lower refractive index than a material forming the LED chip (for example, GaN), the light extraction efficiency may decline.
In the case of using the silicone resin, because its refractive index is lower than that of the epoxy resin, light emitted from the LED chip is likely to be reflected at an interface with the binder, so that the light extraction efficiency may decline further (for example, see Patent document 2).
In response to this, there have been proposals such as a method of setting the refractive indices from the LED chip toward the outer layer that decrease stepwise (for example, see Patent document 3), a method of using an inorganic oxide or the like having a high refractive index as a sealing material of the LED chip (for example, see Patent document 4), and a method of scattering light by using a porous material for a substrate of the LED chip or forming unevenness on the surface of the above-mentioned substrate (for example, see Patent document 5), for example.
Patent document 1: JP 2004-71908A
Patent document 2: JP 2005-93724 A
Patent document 3: JP 61(1986)-96780 A
Patent document 4: JP 2001-24236 A
Patent document 5: JP 2005-191514A
However, the methods proposed in Patent documents 3 to 5 still have not achieved the light extraction efficiency sufficient for the application to an illuminating apparatus or the like, for example.